Posted
by
CmdrTaco
on Thursday February 24, 2005 @03:00PM
from the finally-a-use-for-my-wind-pipe dept.

sanspeak writes "Now you do not have to look for a power outlet to charge your cell phones. Department of Industrial Design at Indian Institute of Technology, Delhi have come up with a mobile turbine which generates around 3 to 4 watts of energy - sufficient to charge a mobile phone. It costs around $4, fits in your pocket and runs on air ;-). What else do you want ?"

That was really funny. It would be good for people who run in rodeos and then go home and ranch their cattle because there is a lot of wind on the praire and they would be riding around on horses, which is a lot of fun.

The wind would blow, and then the battery would get really recharged. They could talk forever:Sample conversation

Customer service: This is a Sprint customer service person, how may help you?

Cowboy Neal: I would like to order some pizza?

Customer service: This is not a pizza place, this is Sprint Customer service

They're not talking about hanging the things out of car windows. A 12V adapter would be better for that, anyway.

Instead, they're expecting that typical environmental wind, especially that found on coasts, will work well enough. The idea is to ease communications access to areas without convenient electricity. (Mountain climbing, anyone?)

Because I've used one of those, and they royally suck. The light is nearly worthless. I blame this on their reliance on an ultracapacitor rather than rechargeable batteries. Batteries would enable the use of more LEDs, making the light a lot more useful. Nothing wrong with Faraday induction, just that's a HORRID example of it.

Also, doing this in a fone would require substantial empty space and weight, neither of which seems to be all that

I can't wait to see people blowing into their phones before they make a call, unless they do what the article recommends:The device will help mobile phone users charge their phones while travelling in a bus, a car or a train. All they need to do is -- place the turbine against the wind flow.In other words, hold it out the window. Can they get sued when people drop their phones, or lose an arm while holding it out the window?

Of course you don't really get any cost saving when sticking it out the window in your own car. The increased air resistance means the cars engine needs to burn more fuel to maintain the same speed, just so your wind turbine can convert that energy into electricity.

It would be easier (and probably more efficient) just to plug the phone into the cigarette lighter adapter.

You'd be better off relying on weather-related wind (or just run really fast, thus powering your phone by biomass).

Lets restate this.... you are really taking energy from the train/bus/car

You increase wind resistance quite a bit just by opening the window. In fact, it has been noted that you are actually better off using the A/C than opening the window, because opening the window decreases your fuel economy more than running the A/C.

Now, unless you have one of those 1980s cell phones that are roughly the size of a boombox of the same era, your cell phone uses less energy than your car A/C.

Great.. A cell phone that charges by air. Now all I need is a light weight air compressor with an efficiency greater than unity and I'll never have to plug my phone in again! At least, I won't have to plug it into anything aside from the turbine and the perpetual motion machine.

I still prefer the alternator strapped to a cat with a slice of buttered toast strapped to its back.

If you think about it carefully, the buttered toast has to be strapped to the cat's feet;-)

Not in the "classical" buttered-toast-on-cat scenario. In the classical scenario, a slice of buttered toast it attached to the back of the cat (usually with duct tape) so that the buttered side is facing up if the cat is standing on its feet. When the cat-buttered-toast object is dropped from any height two laws regarding the components come into play. Firstly, a falling cat will always land on its feet. Secondly, a falling piece of buttered toast will always fall buttered-side down. When the cat-buttered-toast object falls, one of the "laws" will be violated assuming the cat-buttered-toast object does indeed hit the ground. Again, in the classical scenario the cat either ends up perpetually spinning above the ground, or simply floats in mid air.

In your example you are using a non-traditional cat-buttered-toast model in which the cat is placed on top of the buttered toast in such a manner that the cat ends up with buttery paws. This model is not used for various reasons. Firstly, the difficulty of attaching toast to all four paws of the cat is at least an order of magnitude greater than simply attaching the toast to said cats back. Although various attempts at slicing the toast have overcome this difficulty, the amount of effort required is always greater than attaching the toast to the cat's back.

In any event, the results of the non-traditional model are usually the same as the classical. Our cat with buttery paws is dropped from a height and attempts to land on its feet, however the toast that is attached to its feed attempts to land buttered-side down.

Now, it should be noted that defenders of the classical scenario usually point out that the toast, relative to the cat, has already succeeded in landing buttered side down by the nature of it being attached to the cats paws. If the cat were to hit the ground while standing on the toast, it would be akin to someone steping on a slice of toast after it has already landed on the floor, buttered side down. Basically it would be irrelevant as the goal of the toast to attach its buttered side to a surface has already been acomplished.

So, although I used the traditional buttered-toast-on-cat model and the non-traditional models are at least partially flawed, I believe I made the correct decision in its use.

I tried this once on a cat at home (not one of my favorites, fortunately). The cat landed on it's feet at the same time that the bread landed buttered-side down, causing a small tear in space time that instantly pulled the cat, toast, butter container, miscellaneous dishes, the toaster, and 3/4ths of a city block into a parallel dimension where old adages aren't always true. I can't imagine the horror of trying to live in such a place!

What if the cat merely lands on its feet? The buttered toast will never land, and so the complex won't need to hover. That's the advantage of strapping the toast to the cat's feet, if you believe that the toast has not landed when you do so. If it lands, either the unbuttered side of the toast must touch the ground, or the cat's feet must not be down. There is no middle ground where one can land and the other does not, as there was with the previous model.

What if we put the cat between two slices of toast? The slice on the cat's feet would be buttered so that the cat's feet were in the butter, and the slice on his back would be buttered so that the cat's back was in the butter. The toast on the cat's feet will orient itself so as to land butter side down, but the cat and the toast on its back will instinctively correct the positioning so that it would land on its feet. The trouble here is that only one slice of toast wants one orientation, while the other

I attempted this experiment. I tied a piece of buttered toast to my cat's back and dropped him off the side of the table. The cat landed on his feat and the toast slid around his body under the string and hung, butter side down, on his belly. It then slipped out of the string and fell butter side down on the floor.

Granted my experiment might have been more sound with better method of toast attachment, I do believe this proves that neither law can be violated. Were I to more securely attach the toast some other method of getting both the toast butter side down on the ground and the cat on its feet would present itself;)

Poking fun isn't racism. It might be offensive, but it's not the same thing.

Racism is telling people they can't drink from the same water fountains as other people, or refusing to sell a house to them based on their skin color, or herding them into gas chambers, or dragging them behind pickup trucks, or chanting "Death to all ABC" where ABC is the race of your choice.

Joking about an accent which, let's be honest here, can sometimes border on absolutely incomprehensible is possibly in bad taste but defin

Anybody who's ever used a pneumatic tool in a shop would probably say it'd work just fine. However, if you've ever seen the size of a tank needed to hold enough air to actually do some work (25 gallons is small) you'd think twice about carrying that around.

I was thinking of it on more of a large-scale. Imagine if you were off-grid, and instead of having a row of chemical batteries, you kept a series of compressed air tanks.

If it would work and provide enough energy, it would also be an environmentally friendly way to store energy for later use.

Kind of the same idea as pumping water into a tower and then later opening the tower at the bottom and using the flowing water to run a generator. In essence, the water tower is your battery, because it is storing e

airflow isn't the issue; you can regulate the flow at pretty much any level that's suitable. Power density is the important part; in order for it to be a good idea you've got to be able to put more energy into the storage medium than a similar size/weight battery can hold.

The weight issue isn't that much assuming the turbine is lightweight enough. Size is another issue; but carbon fiber wound air bottles can get 2500 PSI ratings fairly easily so it might be doable...

there's this physics law that sais air gets hot when you compress it. If the tank is not insulated it will cool down to room temperature again and you lose quite some energy. There are however examples, there is even a car which runs on compressed air, and in the good old days of steam, they used comp. air locomotives e.g. in ammo factories and other places where you might want to avoid fire.

How long does it take to charge, and wouldn't you have to leave it somewehre with a constant air flow? Like, outside, or in front of a fan, or does it strap to your side so it uses the breeze when you walk?

I can just imagine someone talking and their battery's about to die, and all the other person on the other end hears is "Wait, my phone is dying...hold on a sec *blowing sound* Ok, now where were we..*blowing sound*...Oh yes, about the *blowing sound*..."

I think it might be a little more correct to substitute "wind power" for "air" in the writeup.

Essentially, the idea is to incorporate a windmill to power the phone.

Saying the phone is "Air" powered implys (to me, at least) that some chemical reaction is taking place using oxygen or nitrogen.

It is a cool idea, and the article implies that normal winds are sufficient to power the cell phone.

If the generator is small enough to actually be part of a cell phone, I'd think that scaling the design up might make economic sense for generating normal electric power. Unfortunately, there weren't any specifics, so it is tough to make any extrapolations.

Okay, I'm sorry.. I just can't take it anymore. This is not an innovation by any stretch of the imagination (you say "portable turbine", I say "little windmill"). Second, the application and practicality are extremely limited. Let's look at the scenarios.

Scenario 1: You live someplace windy Supposing you take this turbine, stick out your window that receives good airflow in an area that has *continuous* wind (let's say you live in a lighthouse). Gi

Tell me why if this model produces 3 - 4 watts of energy why they can't cover the blades of larger windmills with these things or better yet design the blades so they have edge holes with these things inside.

The wind blows the large blades which causes air to flow through the smaller fans.

Of course you could probably put up walls of these things in windy areas and get the same results.

What this tells me that the manufacturers are idiots and we can improve it.

If we're not even close to producing one that is 59% efficient why wouldn't something like this help improve it. From my thinking it would help in several ways:

1) These turbines are designed for everyday use which means that they have to be cheap and replaceable as they die.2) They produce 3 - 4 watts per device. This is not insignificant in larger numbers. How many rivets do you see on large buildings?3) By br

Check this [earthsci.org] you need bigger wing span to generate more power, also the less complicated design, less maintenance time. With large number of small things... although they might be cheap enough not to care about that.

Tell me why if this model produces 3 - 4 watts of energy why they can't cover the blades of larger windmills with these things or better yet design the blades so they have edge holes with these things inside.

There is no such thing as a free lunch (1st law of thermodynamics). The drag produced by the turbines extracting energy slows the speed of the windmill blades reducing the power delivered to the main generator so you gain nothing by adding those (more likely you will lose since the main generator is less efficient at slower speeds).

Coincidently, this is the same problem with charging the cell phone by clipping this device to
the outside of the window while riding in a bus, train, or car. The vehicles engine needs to consume more energy to offset the drag produced by
the turbine. Granted it is small compared to the amount of energy used to move the vehicle in the first place but it would be more energy efficient to connect the phone to the vehicles alternator
than to convert the engines rotory motion to motion induced "wind flow" and then the wind flow back to rotary motion.

Now could you make a windmill with no main generator and use a large number of small turbines
instead? Yes but it probably would not work well at all. In fact, it would probably work less well than just pointing the turbines into the wind which in turn would not work very well at all.
The problem is a serious impedance mismatch. Turbines want high pressure/high airflow.
A windmill blade tip will be travelling at a lower linear velocity than the air that turns it.

Incidently, power from wind is proporional to the cube of the wind velocity. Generators are inefficient at low speeds.
Modern windmills adjust to different wind velocities by feathering the blades to try to run the generator at a relatively constant speed. In really high winds they turn the blades parallel to the airflow to avoid destroying the generator and gear train.

Note that since it was described as a turbine and not a "wind turbine" (which is normally a very different beast) and described it as fitting in a pocket, I am imagining a device with multiple disks with the edge shaped into blades inside a tube like you might find in a jet engine or gas fired power plant (every other disk is stationary or counter rotates to restore longitudinal airflow). A friend built an toilet paper roll cardboard tube sized device out of sheet metal in this topology that was demonstrated with the air from a shop vac that would be about the right size for a cell phone charger.
If that is not the topology used., then some of what I have said will not apply but much of it still will.

Whatever turbine topology you use on your windmill blades, you are converting from wind to rotary motion twice and therefore are reducing the efficiency by around 60% compared to doing so once even if it is well designed and operating at optimal wind speed. And poor performance at low speeds will be made even worse by being being run twice through the innefficent portion of a non-linear transfer function.

Back to the original article, the usefulness of this is likely to be very limited since people in India who don't have electricity aren't likely to spend a lot of time running around in vehicles every day to charge their phones. A small roof mounted windmill would probably be a lot more practical. It may have some use as a travel charger for people who will be traveling to distant points but not be staying for very long (such as tourists).

The little generators that run headlights on a bicycle might be another alternative for charging a cell phone. With a stand, pedal power can even be used while stationary. Someone
built a generator stand for a bicycle
[erols.com]
that was capable of generating as much as 260W (100W seems more likely for an extended period of time).

A small solar panel with built in battery (so you don't need to leave your cell phone on char

What else do you want?
Summaries that are closer to the reality of the article.
It costs around $4.
"The technique is not yet commercialised but the department has sent a proposal to the ministry of science and technology to help manufacture the turbine on a large scale, Das said."

I aways wondered if this could be done. I consided
hooking such a device up to the overhead air blowers they
have on commercial airplanes to charge cell phones and laptops. There is probably a FAA law against this however.

This is an incredible step forward, but not for us people who can already charge our cellphones in our cars, in the office, and at home, and just want to charge them in the supermarket, too.

Think wider.

Think mine detectors.

Think Cambodia, Rwanda, Ethiopia.

People who really, really need some piece of low-power electronic equipment, and DON'T have four different charging stations already, and whom it will cost an arm and a leg - literally! - if they are careless.

I wish that the editors would only post stories that actually had some specs or detailed description of the tech behind new devices. Just a press release and some hype would only warrant a couple of sentences.

I can just see the next version of the SCOTTEVEST [scottevest.com] with turbines on the hood, combined with the solar epaulettes... perhaps voltaic electrodes in boots for when trudging through salt marsh?

Now if your cell battery starts to get low while chatting to your friend while driving, you can just crank up your A/C, roll down your window, and hold one arm out the window while you eat and change the radio station with the other.

Or for when your battery is a little low, but you just really need to call someone - you can blow on your phone for a few minutes, then pass the phone to a friend (if you have any left) and they can call 911 since you're hyperventilating.

Seriously, in public transportation - of the times when you can hold your phone up to a window - you might want to purchase some tshirts that say "I'm an idiot, steal my expensive phone after I get off the bus". Any other times, you should be able to find a much more efficient and timely manner of charging your phone. Windows down + A/C up == your car is burning excess energy.

In Korea, only old people want to stop the country jokes, you insensitive clod.

Of course, no one posts country jokes...in Japan!

I don't know why people want to stop the running jokes so much. (Hell, bitching about the running jokes seems to be getting as bad as the jokes themselves.) Without our subculture [wikipedia.org], Slashdot wouldn't be what it is today. We'd probably all just sit around thinking of Natalie Portman while pouring hot grits down our pants...except in Nebraska.